1. Field of the Invention
The present invention relates in general to cans such as beverage cans and, more particularly, to a structure in such cans for simply achieving detachable coupling of two or more cans.
2. Description of the Prior Art
Most of typical cans have been produced and commercialized in handheld sizes but have no means for their detachable coupling to each other. Therefore, most of the typical cans having no detachable coupling means are simply kept or carried with a person when one or two cans need keeping or carrying with the person. This creates a problem that it is very difficult to keep or carry them when three or more cans need simultaneously keeping or carrying with the person.
As is well known to those skilled in the art, the cans are conventionally formed of iron thin plates or aluminum thin plates which should be saved from the viewpoint of saving of resources. In order to save the resources, the emptied cans made of iron or aluminum thin plates need recovering and reproducing. However, since most of the typical cans have no means for coupling them to each other, the emptied cans are inevitably discarded separately, thus causing a problem in that they must be collected one by one when recovering them for their recycling. Particularly when the typical cans having no detachable coupling means are discarded separately in the open air, they will be scattered in the forest or in the sands in the open air. Hence, when the emptied cans separately discarded in the open air are collected for their recycling, they must be picked up while being found out one by one, and this creates problems for can collectors. Hence, the cans separately discarded in the open air may be neglected. This not only runs counter to the recent trend of resource saving but also causes environmental pollution.
In the prior art, there have been proposed detachable can coupling structures and detachable can coupling methods for overcoming the above problems caused by the typical cans having no coupling means. However, the prior art structures and methods for coupling the cans are not practically used because of their structural problems as will be described later herein.
Japanese Utility Model Laid-open Publication No. Sho. 54-58350 discloses a can having, at its top and bottom, a screw type coupling structures for vertically detachably coupling the cans to each other. However, this can causes a hygienic problem in that the contaminants on its top coupling structure may be introduced into the human body when drinking the beverage from the can. That is, the screw type top coupling structure has recesses between its threads, and contaminants may be present in those recesses. In this regard, the contaminants remaining on the top coupling structure may be directly introduced into the human body along with the beverage when drinking the canned beverage, thus causing a hygienic problem. In addition, each of the top and bottom coupling structures of the above can is shaped in the form of a predetermined width of annular strip extending from the top periphery or the bottom periphery of the can. The top and bottom screw type coupling structures of the can are thus weak in their bending strengths so that they are apt to be deformed or bent even when they are subjected to a weak outside shock. When either of the top and bottom coupling structures of the can is deformed by an outside shock, this can cannot be coupled to another can at its top or bottom. In this regard, the above can is attended with a problem in its practical use.
Japanese Utility Model Laid-open Publication No. Sho. 63-1727 discloses a pair of cans having another type of can coupling structure for detachably coupling the two cans to each other. In this device, the can coupling structure comprises a slot flange extending upwardly from the top periphery of the bottom can to a predetermined length and slitted at predetermined positions so as to form diametrically opposed locking slide slots in an L-shape. In order to engage with the above L-shaped locking slide slots of the bottom can for achieving the detachable coupling of the cans, the top can is provided with a pair of locking slide projections extending outwardly from its bottom side at positions corresponding to the above locking slide slots. In accordance with this device, the two cans or the top and bottom cans are coupled to each other by bringing the projections of the top can into engagement with the L-shaped slots of the bottom can. However, when the top periphery of the bottom can is partially slitted so as to form the L-shaped locking slide slots, the can may achieve no desired hermetical sealing due to the structural limit of the typical can. Moreover, even when the L-shaped locking slots are formed on the top periphery of the can while providing the can with the desired hermetical sealing, another problem is caused by the material of the can. That is, since the can is made of the iron thin plate or the aluminum thin plate as described above, the slot flange of the bottom can having the L-shaped slots is apt to be deformed or bent by an outside shock, thus failing in its engagement with the projections of the top can. Particularly when the can is made of the aluminum thin plate, which plate is softer and shows less elasticity than the iron thin plate, the above problem of bending deformation of the slot flange will become worse. Accordingly, this coupling structure can not be adapted to typical cans.
People, young and old, men and women in many parts of the world enjoy themselves over the canned beverage irrespective of the above problems caused by the prior art cans so that a new can needs proposing. Such a new can should have a new structure for overcoming the above problems of the prior art cans and should provide for detachably coupling the cans to each other when keeping and carrying them with the person. The recent trend of saving of resources promotes such a proposal of the new cans having the new detachable coupling structure suitable for making the emptied cans easily simply recovered for their recycling.